A hydrogen-producing fuel processing system includes a fuel processor that produces hydrogen gas from a carbon-containing feedstock, and in some embodiments, water. Examples of suitable fuel processors include steam reformers and autothermal reformers that utilize a reforming catalyst to produce hydrogen gas from the carbon-containing feedstock and water. A fuel cell stack produces an electric current from fuel and an oxidant. A fuel processing system may, but does not necessarily, include a fuel cell stack that produces an electric current from the hydrogen gas produced by the fuel processor. Some fuel cell stacks receive a fuel other than hydrogen gas, such as methanol, and may form a portion of a fuel cell system that does not include a hydrogen-producing fuel processor.
Examples of suitable carbon-containing feedstocks include hydrocarbons and alcohols. Methanol is an ideal feedstock for use in a fuel processing system, especially when the hydrogen gas produced in the fuel processor is delivered to a low-temperature fuel cell stack, such as fuel cell stacks that include proton-exchange membrane (PEM) fuel cells or alkaline fuel cells. Methanol may also be used as a fuel for some fuel cell stacks, such as direct methanol fuel cell stacks.
However, methanol also poses health hazards because it is a toxic alcohol (by inhalation of vapors, contact with the liquid, and ingestion of the liquid). Methanol also has very little odor and is considered tasteless. Thus, it is difficult to smell methanol if it is spilled or leaks from a storage device, fuel processor, transport conduit, or the like. Further, a person or animal could mistakenly ingest methanol due to its lack of taste and/or odor, for example believing it to be a harmless liquid, such as water. Therefore, there is a need for a suitable method for detecting methanol that leaks, spills, or is otherwise unintentionally released. Conventional odorants used with natural gas are not suitable for use in fuel processing systems because these odorants are alkyl thiols that poison the reforming catalyst, thereby destroying the utility of the fuel processor.